Many current enterprises have large and sophisticated networks comprising switches, hubs, routers, servers, workstations and other network devices, which support a variety of connections, applications and systems. The increased sophistication of computer networking, including virtual machine migration, dynamic workloads, multi-tenancy, and customer specific quality of service and security configurations require a better paradigm for network control. Networks have traditionally been managed through low-level configuration of individual components.
In response, there is a growing movement, driven by both industry and academia, towards a new network control paradigm called Software-Defined Networking (SDN). In the SDN paradigm, a network controller, running on one or more servers in a network, controls, maintains, and implements control logic that governs the forwarding behavior of shared network switching elements on a per user basis. Typically, the shared network switching elements are software switching elements. A software switching element brings many features that are standard in a hardware switch to virtualized environments. The software switching element can also be more flexible than the hardware switch. For instance, the software switching element can be programmed to emulate a traditional switch pipeline or can be programmed to extend for new models.
One of the main challenges in developing such a software switching element is performance. A hardware switch has application-specific integrated circuits (ASICs) that are specifically designed to support in-hardware forwarding. The problem with a software switch is that it operates on a host (e.g., ×86 box), such as a hypervisor. Thus, methods for increasing the performance of the software switching element are needed.